Stop Huntingdon Animal Cruelty (SHAC) was started by Greg Avery, his wife Natasha Avery and former wife Heather Nicholson in 1999 after a Channel 4 documentary highlighted animal abuse at HLS’s base in Woolley Road, Alconbury.

Its aim was to force the closure of HLS – Europe’s largest animal testing laboratory for the pharmaceutical and chemical industries – but, despite a temporary resettlement of the company to America, SHAC failed to achieve its main task.

A statement on SHAC’s website said: “After more than 10 years of organising the SHAC campaign and having sent shock waves throughout the entire vivisection industry, our opposition has evolved.

“The global animal abuse and legal landscapes have changed and so it’s time for us too, to change our tactics. Although we’re announcing the closure of the SHAC campaign, it will always be an important part of our history and a reminder of the ingenuity and power of the animal rights movement.”

SHAC campaigners carried out a series of peaceful protests but will be more synonymous with violent attacks and death threats to staff at HLS and other companies involved with the lab. In 2001, HLS managing director Brian Cass was ambushed near his home in St Ives by three people armed with pickaxe handles. And Andrew Gay, marketing director for HLS, was temporarily blinded when he was sprayed in the face with a chemical.

Campaigners were also linked to attacking a businessman, who had connections to HLS, and leaving his unconscious body next to his barn, which they set alight.

Hoax bombs were planted and letters were sent to HLS employees’ neighbours claiming they were living next to paedophiles.

The group also claims to have sunk a boat belonging to an executive at a bank which was funding HLS.

Seven SHAC members were jailed in 2009, including leader Greg Avery, who was sentenced to nine years after admitting conspiracy to blackmail. A further five were imprisoned the following year.

A statement from HLS said: “The decision by SHAC to end the campaign is welcomed by Huntingdon Life Sciences and all those associated with the company.

“Even during the early years when extremism was at its height HLS still managed to successfully grow its research business.

“The UK environment for the use of animals in biomedical research has improved greatly in recent years, and this is the result of action taken by law enforcement agencies to control animal rights extremism.”

The unlawful action against HLS – and the work to prevent it – continued as recently as earlier this year when Debbie Vincent, of St Marks Road, Easton, Bristol, was jailed for six years after being found guilty of conspiracy to blackmail in relation to her 10-year association with SHAC.